A bone tissue consists of osteocytes and an intercellular matrix, among which the latter is greater by weight. The intercellular matrix includes collagen fibers and inorganic constituents. This bone tissue undergoes constant remodeling to alter its form and to maintain the concentration of calcium in the blood. Usually, the bone weight of an adult hardly changes by the remodeling since the amounts of bone resorption and bone formation are equal. However, the condition that the amount of bone formation is less than to that of bone resorption causes osteopathy accompanied by a decrease in bone weight, including osteoporosis. The decrease in bone weight can be categorized into the following 3 groups by the factors considering the conditions of the bone remodeling: (1) decrease in bone weight associated with increased bone resorption function including osteoporosis in the early postmenopausal stage, hyperthyroidism or other diseases; (2) decrease in bone weight associated with a decrease in bone resorption and bone formation functions including senile osteoporosis, diabetic osteoporosis or the like; (3) decrease in bone weight resulting from an amount of bone resorption greater than the amount of bone formation despite of normal bone resorption and bone formation functions (for example, because of low calcium intake).
Thus, the crisis rate of osteoporosis increases for older people and dramatically rises in postmenopausal women.
Today, typical methods for treating or preventing osteopathy accompanied by a decrease in bone weight include (1) supplementing calcium/magnesium intake; (2) administration of calcitonin; (3) employing exercise therapy (particularly for aged people); (4) administration of active vitamin D (particularly for aged people); (5) administration of estrogen preparations (particularly for postmenopausal women) and (6) administration of parathyroid hormone; among others. These methods are usually carried out in combination, depending on the causes.
However, among the above methods, hormone preparation can not be used in prevention and has a high risk of side effects when used in treatment. Therefore, hormone preparation has to be used under a doctor's strict supervision. Further, other methods which do not use the hormone treatment in combination have not succeeded in producing satisfactory results. Accordingly, the development of side-effect-free treatments or prevention methods has been desired and many suggestions have been made on it. Typical research includes focusing on minerals having high absorption rates and combinations of these minerals (Japanese Unexamined Patent Publications No. 1987-501843 and No. 1994-500552), the suggestion focusing on the combined use of minerals and a substance which increases absorption rates of minerals (Japanese Unexamined Patent Publications No. 1994-40922 and No. 1994-70726), the suggestion focusing on the substance which improves the function of osteocytes (Japanese Examined Patent Publication No. 1995-76235 and Japanese Unexamined Patent Publication No. 1990-303457), among others.
However, the above suggestions can not satisfactorily prevent or treat osteopathy accompanied by a decrease in bone weight and the development of more effective methods is anticipated.
The periodontium, which supports the teeth and absorbs external force applied to the teeth, consists of the gingiva, the periodontal membrane, the alveolar bone and cementum. Advanced atrophy of gingival tissues and disease accompanied by the resorption of alveolar bone may result in permanent tooth loss. This greatly inconveniences a person's daily life, and is known to seriously affect a person's overall health by causing diseases such as nutrition disorders due to indigestion and the like. Although various treatments have been tested to prevent the resorption of important alveolar bone in the periodontium, improved prevention and treatment of atrophy of gingival tissues and the resorption of alveolar bone is desired.
Incidentally, among the three diseases having high death rate in Japan, cerebrovascular diseases and heart diseases are said to be closely associated with hypertensive diseases. Essential hypertension, which accounts for about 80% of all cases of hypertension, is associated with autonomic nerve and humoral factors including catecholamine and angiotensin in a complicated manner. In addition, it is known that the incidence rate of hypertension different between the sexes, that is, the incidence rate is higher among men than women. It is also confirmed that the incidence rate of hypertension increases among women over 50 years of age in their climacteric because of menopause. Women over 60 years of age have the same incidence rate of hypertension as men in the same age range.
Currently, hypertension can not be completely cured even by the administration of antihypertensive agents (medicines). Recent advances in food chemistry have led to the discovery of biologically active substances which are derived from various foods. Since these antihypertensive agents derived from foods are highly safe and economical, they are considered particularly useful in preventing or treating hypertension and diseases resulting from hypertension for long-term administration.
Incidentally, an experiment using cultured osteoblastic cell strain has recently revealed that a stilbene-type compound, resveratrol, accelerates the proliferation of osteoblastic cells, accelerates the activity of alkaline phosphatase and enhances the activity of prolyl hydroxylase (Biochemical and Biophysical Research Communications, Vol. 253, No. 3, pages 859–863, Dec. 30, 1998).
However, this report is simply an in vitro experiment using osteoblastic cells and it does not clearly indicate that the stilbene-type compound containing resveratrol is effective in treating or preventing diseases accompanied by a decrease in bone weight in complicated living organisms. In particular, it is unknown if stilbene-type compounds including resveratrol are effective treatment for diseases accompanied by a decrease in bone weight during and after climacteric or useful for treating or preventing hypertension and diseases resulting from hypertension.